Engine in development could cut Mars travel time to three months

Fusion reactor would use deuterium and lithium-6 crystals.

Humanity has been in space for a while, but we really haven't managed to go very far. Carl Sagan once said that "the surface of the Earth is the shore of the cosmic ocean, and recently we've waded a little way out, maybe ankle deep"—that was in 1980, and we haven't risked testing the water any deeper since then.

One of the main reasons for that, though, is that space is so frustratingly massive. Voyager 1 is the fastest man-made thing ever, but 17 kilometers per second is a tiny fraction of the speed of light. Even getting to one of our nearest neighbors, Mars, would take six to eight months using conventional spaceship engines. Ideas like warp drives are still theoretical, and unlikely to be seen within our lifetimes. However, it might be possible to cut that trip to Mars down to as few as three months using a form of fusion fuel—"dilithium crystals." Yep, just like Star Trek.

It's not quite the same, of course. In the sci-fi series, the crystals are a rare substance that the crew spend an inordinate amount of time searching for, and their engines can use it to travel faster than the speed of light. This engine, currently under development at the University of Hunstville by a team working in collaboration with Boeing, NASA and the Oak Ridge National Laboratory, would by comparison be about twice as fast as the best current technology.

According to Txchnologist, General Electric's online tech magazine, this fusion reactor would be fueled by "a few tons" of deuterium (a heavy isotope of hydrogen) and lithium-6 (a stable molecule of lithium) in a crystalline structure‚ hence the "dilithium crystal" claim. Technically, dilithium is a molecule with two covalently bonded lithium atoms, while lithium-6 features six bonded atoms, but we can forgive them for the temptation of using a little poetic license. When the deuterium and the lithium-6 are forced together under high pressure they undergo a fusion reaction—a process which they're still trying to turn into a net producer of energy. While fusion isn't yet a viable fuel source, recent developments in the field seem to indicate that we can't be far away.

The engine, dubbed the "Charger-1 Pulsed Power Generator", would be constructed in space along with the rest of the spaceship to avoid the tricky engineering difficulties of getting all that delicate fusion equipment up through the atmosphere—just like the International Space Station. Once ready, the reactor would be engaged, and millions of amps are passed through super-thin lithium wires in 100 nanosecond pulses—this could generate up to three terawatts of power. Those wires vaporize into plasma, which is collapsed onto the core of deuterium and lithium-6, inducing a fusion reaction.

The energy from that would be forced out the back of the ship in a so-called "z-pinch" using a "magnetic nozzle," a component which the team are also developing. The engine's potential top speed? Over 100,000 km/h. That's roughly the same speed at which the Earth orbits the Sun.

However, as Business Insider points out, it's likely that any commercial or scientific use of the technology will only be if the US army allows it, as the research is being conducted using equipment repurposed from military projects. And, again, that depends on developing a fusion reactor that generates more power than it consumes.

The dilithium of Star Trek was not merely a molecule with two atoms of lithium, though—it was always described as its own element, and a periodic table seen in one episode listed it as having atomic weight 87 (which would place it between Rubidium and Strontium if its atomic number followed normal convention, but we can probably assume that dilithium is a bit unusual and obeys laws of molecular physics as yet unknown to our primitive science).

Hopefully those astronauts trained to maintain and run these dilithium crystal fusion reactors will not suffer the ignominy of their colleagues asking that they give status reports in Scottish accents. Even if it would be quite funny.

from what I understand we've been able to get to Mars in about 6 months its just the issue of slowing down to get into orbit that kills us (fuel wise). not that I'm not excited about any new engine technologies, but when considering cost, its way more efficient to travel at economical speeds than it is to travel fast in space... especially considering the maximum number of G's we can sustain as humans.

A small correction on the science in the article. They are talking about making an engine out of 6Lithium deuteride. 6Li is not a molecule composed of six lithiums, but an isotope of lithium like deuterium is an isotope of hydrogen (however, unlike deuterium which has one more neutron than hydrogen, 6Li has one less neutron than the most abundant isotope 7Li)

The source article states it as Li6 (which, using conventional nomenclature) would be six lithiums, but then goes on to state that it is an isotope of lithium. I believe that they just got the nomenclature wrong, and that the engine is in fact using 6Li because 6Li is a key component in providing tritium (an isotope of hydrogen one neutron heavier than deuterium) to fusion reactions.

So you got the power source but what is the engine that produces movement?

Per the article, they use the reactor's magnetic containment to also vent the plasma, and thus would be functionally the same as any other reactive thruster like we already use. The expelled mass produces an equal and opposite force on the engine, pushing the two apart, exactly the same as a standard solid- or liquid-fuel rocket, a jet turbine, etc.

This is fantastic news! Who cares about worldwide hunger when we can spend trillions playing with rocks on Mars?!

Many of the advancements made via research into technologies relating to manned spaceflight (and even unmanned) have had significant and direct impact on people on the ground. From MREs to computers to velcro. One aspect of a manned trip to mars will still be providing food as well as air and water purification, for a minimum 6 month journey (3 out, 3 back, and zero time to do anything while they're there). It's not illogical to think that related advancements might be applied to fighting polution and improving efficiencies planetside.

Furthermore, the article states that the project is also dependent upon the achievement of a fusion reactor with a net power gain, which would be a massive breakthrough, and provide enormous amounts of extremely cheap, fairly clean power (and from what I understand, relatively safe, as well). If you aren't up to speed on fusion, we've had reactors built for quite some time. The problem we run into is that the magnetic containment field requires more power to maintain than we're able to extract from the reactor; a net power loss. A breakthrough allowing us to either use less power for containment, extract more power from the reaction, or a combination of the two, would give us the net power gain that we need. Needless to say, this would be a massive boon to everyone.

As antiworldly said, Li-6 is an *isotope* of lithium with 6 nucleons (protons and neutrons), not a molecule with 6 atoms.

Also, fusion propulsion does not depend on fusion power. A fusion drive that requires a fission reactor (or even solar panels) as a power source would still give better performance than a plain plasma drive using the same power input. It may even perform better than a self-powered fusion drive of similar size, depending on how heavy the power generation equipment is and how much power it has to pull out of the exhaust. You'll need some capability for firing a propulsion pulse from an outside power source anyway, or you'll never fire the first pulse.

"The dilithium of Star Trek was not merely a molecule with two atoms of lithium, though—it was always described as its own element, and a periodic table seen in one episode listed it as having atomic weight 87 (which would place it between Rubidium and Strontium if its atomic number followed normal convention…"

That would make it Francium in the periodic table that our science uses.

Donnicton: I think you mean four-tenths of one percent of the US budget. (I'm a big space enthusiast, but even I would consider 40% of the US economy to be an excessive budget for NASA. :-) Though I wonder just what you could get for those six trillion dollars if you had them to play with...)

As for the article, I'd love to see a working fusion drive, but this seems a little gee-whiz. So all we have to do is get fusion up and running (but we're getting close to breakeven! something that as far as I can tell has been stated to be the case as long as I've been alive) and then do the same with magnetic pinch bottles? It's basically blue sky research at this point.

Which I'm all in favor of. But on the reporting side, I much prefer the more cautious treatment of the linked Txchnologist article: ("researchers to begin... experiments"; "major problems to solve") to the sensationalistic "could cut Mars travel time to three months" headline.

This concept has long been proposed, don't leave those poor humans out there in interplanetary space for a year and a half in microgravity doing some kind of fancy Newtonian billiard shot with conventional propulsion, give it some kind of heavy duty nuke power and get 'em there quickly.

Considering this engine doesn't even produce net power yet... I'm not holding my breath. Also time to get to Mars isn't that bad at 6 months, there's a whole lot of other issues that a more efficient engine would solve...

This is fantastic news! Who cares about worldwide hunger when we can spend trillions playing with rocks on Mars?!

...Are your other 671 posts as painfully stupid,or you made a special effort on this one trollpost? Because aside from the other stuff pointed out in response ^, I'll have to remind you that 'playing with some rocks on the Moon' brought us a plethora of new materials, technologies and yes,even new ways to treat,store and utilize foodstuffs.

I think it's hilarious we still consider propulsion a form of travel. In 30-50 years, we will more than likely find a form of an engine that does not require some kind of reaction that pushes us forward, but more like something that moves us more efficiently. The the difference between a jellyfish and an eel in terms of movement.

I think it's hilarious we still consider propulsion a form of travel. In 30-50 years, we will more than likely find a form of an engine that does not require some kind of reaction that pushes us forward, but more like something that moves us more efficiently. The the difference between a jellyfish and an eel in terms of movement.

This is jibberish... Jellyfish and eels move in fundamentally the same exact way: by pushing against their surroundings. In a vacuum, there are no surroundings to push against, so you have to bring your own mass to push against...

A small correction on the science in the article. They are talking about making an engine out of 6Lithium deuteride. 6Li is not a molecule composed of six lithiums, but an isotope of lithium like deuterium is an isotope of hydrogen (however, unlike deuterium which has one more neutron than hydrogen, 6Li has one less neutron than the most abundant isotope 7Li)

The source article states it as Li6 (which, using conventional nomenclature) would be six lithiums, but then goes on to state that it is an isotope of lithium. I believe that they just got the nomenclature wrong, and that the engine is in fact using 6Li because 6Li is a key component in providing tritium (an isotope of hydrogen one neutron heavier than deuterium) to fusion reactions.

Agreed. The article also favorably references Rossi's "E-Cat" device which purports to extract excess energy by fusing hydrogen and nickel into copper. The problem with that is the nuclear binding energies don't work out -- the last I checked the general belief was Rossi was discounting the energy he used to heat the mixture in the first place, or missing some chemical reaction between his device and inputs. Add to this Rossi's history of fraud and I think it is still best to be highly skeptical of Rossi.

I attribute it to Ars Technica's generally high-quality science writing that I'm surprised when an article is so confused as this one. There does appear to be something interesting about the Huntsville research, but it didn't make it into this article.

I think it's hilarious we still consider propulsion a form of travel. In 30-50 years, we will more than likely find a form of an engine that does not require some kind of reaction that pushes us forward, but more like something that moves us more efficiently. The the difference between a jellyfish and an eel in terms of movement.

You realize those both work the same, right? The movement to achieve it is different, but both work by pushing on the water, resulting in the water going one way and the animal going the other.

Rossi's "E-Cat" device also mysteriously produces copper with isotope ratios identical to natural copper. And iron, for some reason. And a distinct lack of the lethal radiation to be expected from such reactions producing the thermal output he claims.

And attempts by other parties to measure the claimed heat production are already showing severe problems with Rossi's measurements of input power...

"The dilithium of Star Trek was not merely a molecule with two atoms of lithium, though—it was always described as its own element, and a periodic table seen in one episode listed it as having atomic weight 87 (which would place it between Rubidium and Strontium if its atomic number followed normal convention…"

That would make it Francium in the periodic table that our science uses.

Making for quite the oddity if it ever showed up in a stable crystal form (pesky thing has a high end half life of about 20 minutes).